This invention relates generally to large door structures and appurtenances, and more specifically to a large overhead opening door apparatus with suspension structure, combination manual and automatic powered opening mechanism and lock mechanism for buildings constructed to conform to sloping terrain.
Large overhead opening doors have been in use for some time in large building structures wherein opening a space of substantial size is necessary to allow entry and exit of large objects. A typical application for such large doors is in airport hangars wherein the door space must be large enough to accomodate entry and exit of aircraft. Since the doors are quite large, an ever pervading problem involves opening and closing the doors. This problem is compounded if the building is built on terrain that is not level and with a floor that conforms to such terrain, which is often ecomonically feasible especially for relatively long buildings such as hangars which would require a considerable amount of excavation and fill to provide a level floor, not to mention the otherwise required artificial grading of the surrounding parking aprons and approaches to the hangar. It is also desirable to have a suitable locking mechanism to prevent the large doors from being opened by unauthorized personnel or adverse wind conditions. The present invention provides door apparatus for aircraft hangars which are built with structures and floors that conform to sloping terrain on which they are built and which can be readily opened and closed both manually and automatically and which can be locked in the closed position when not in use.